Brush-holder for dynamo-electric machines.



T. S. ALLEN. v BRUSH HOLDER FOR DYNAMO ELECTRIC MACHINES.

APPLICATION FILED TEB.28,1910.

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UNITED STATES PATENT OFFICE.

THOMAS S. ALLEN, 01 MILWAUKEE, WISCONSIN, ASSIGNOR, BY I MESNE ASSIGNMENTS,

TO ALLIS-CHALMEBS MANUFACTURING COMPANY, A CORPORATION OF DELA- WARE.

BRUSH-HOLDER roa DYNAMO-ELECTRIC MACHINES.

Patented Jan. 13, 1914.

Application flied February 28, 1910. Serial No. 546,559.

To all whom it may concern Be it known that I, THOMAS S. ALLEN, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Brush- Holders for Dynamo-Electric Machines, of which the following is a full, clear, and exact specification.

This invention relates to brush holders for dynamo-electric machines, and particularly to brush holders adapted to be employed with commutators of high speed machmes.

In high speed direct current machines, there is frequently considerable sparking and chattering of the brushes and the op H eration of the commutator and brushes is otherwise unsatisfactory particularly when brush holders having spring actuated pres sure fingers or followers are employed. This is duelargely to slight irregularities of the rapidly revolving commutator surface and to the fact that the pressure fingers which have small inertia, are set in rapid vibration by oscillation of the springs caused by sudden outward movements of the brushes.

The object of the present invention is to provide a brush holder which is especially adapted for use on high speed machines and has a construction such that the vibration of the brush and pressure finger, due to slight irregularities on the commutator surface, will be reduced, and the efiicienc and operation of the commutator and brusi will be improved.

To reduce the vibration of the brush and pressure finger or follower I provide on the latter, preferably at the outer free end thereof, a weight which increases the inertia of the ressure finger and renders it less susceptible to vibration. Preferably the pressure finger does not bear directly on the brush, but a yieldable member such as a spring is arranged between the brush and the pressure finger, so that when the brush is moved outwardly byan irregularity on the commutator surface very little or no movement whatever will. be transmitted to the pressure. finger on account of its increased inertia proyided by the weight and because theyielilable member between the *3 brush and pressure fi'nger will give or yield sufiici'ently to accommodate the movement of the brush.

7 the same.

Figure 1 is a side elevation of a brush holder constructed in accordance with the preferred form of my invention, the holder being provided with a brush which bears against theicommutator, a portion of which 1s also shown; and Fig. 2 is a plan view of Referring now to the figures of the drawmg, 10 represents a cast metal brush holder body which is provided at one end with a rectangularly gshaped brush guide or socket 11', which receives a brush 12, the inner end of which is adapted to bear on the commu- I tator 13, the brush being connected to the brush holder body by the usual shunt conductor 12 The brush holder body is pro- I vided also with an annular socket 14 adapted to receive a supporting stud to which the brush holder may be secured by means of a set screw 15, and extending outwardly from the rear portion of the holder is a pair of arms 16 to the free ends of which is pivotally secured by means of a pin 17 a forked pressure finger or follower 18, the free end of which preferably extends over and is substantially inline with the brush 12. The follower is pressed yieldingly toward the brush holder by means of a spring 19, one end 20 of whicli is connected to the brush holder body, and the opposite end 21 of which is connected to a member 22 adapted to engage in any one of a number of notches 23 generally provided in the brush holders of the type here shown.

In the usual brush holder construct-ions, the follower bears directly on the brush and inasmuch as it has very little inertia, any slight irregularity on the surface of a high speed commutator will throw the brush and follower outward, stretching the spring, and as the irregularity passes the brush and the latter again moves inward, the tension of 105 rest and tends to cause the pressure finger and brush to vibrate, producing more. or less of a chattering noise and sparking at the commutator surface. To avoid this vibration in the brush and follower, Iprovide on the follower a weight 24 so as to increase its inertia, the weight being preferably cast integral with the follower and being located at its free end opposite the brush, and I arrange between the follower and brush a yieldable member 25 which in this case is in the form of a leaf spring secured to the follower.

By providing on the pressure finger the weight 24 and by arranging the yieldable member 25 between the pressure finger and the brush, the vibration of the brush and finger is greatly reduced for the reason that it there is an outward movement ofthel brush due to a slight irregularity on the commutator surface, the spring 25 will yield suflieiently to accommodate this movement without causing any material shifting of the pressure linger and a stretching of the spring 19 chiefly because of the inertia of the pressure finger produced by the addition of the weig 24 at its outer free end. It is not essential that the weight be at the free outer end of the follower, but I prefer that it be so located for the reason that when located as shown it is more etfec tive than if it'were distributed over the Copies of this patent may be obtained. for five cents each, by addressing the Commissioner Washington, D. 8.

pressure finger or were arranged nearer the pivotal support 17.

I do not desire to be confined to the exact details shown but aim in my claims to cover all modifications which do not in volve a departure from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent is I 1. In a brush holder, a body portion having a brush guide or socket, and a spring actuated pressurefinger pivotally mounted on the body portion, and provided at its free end with an integrally formed weight to increase its inertia, and a spring connected to the pressure finger intermediate its ends and adapted to engage the brush 2; In a brush holder, a body portion having a guide for a brush, a spring actuated follower having a weighted end portion and adapted to hold the brush against the collector surface, and a spring attached to said follower intermediate its pivotal point and the weighted end portion and bearing on 7 said brush.

Milwaukee, W'isconsin, February 9,1910.

In testimony'whereof I afiix my signature, in the presence of two witnesses.

THOMASS; ALLEN. Witnesses: y

GHAs. L. BYRON, Ron. E. STOLL.

of Patent.- 

